A plain sedimentation tank with a length of 10 m, width of 5 m, and a depth of 2 m is used in a water treatment plant to treat 1 million litres of water per day. The surface overflow rate in the sedimentation tank is
1
10 m3/m2/day
2
15 m3/m2/day
3
20 m3/m2/day
4
50 m3/m2/day